1. Field of the Invention
The invention generally relates to an optical element and a light source, in particular, to a light guide plate and a backlight module.
2. Description of Related Art
A light guide plate in a conventional backlight module has a plurality of optical microstructures. The optical microstructures may make total reflection of a light beam travelling in the light guide plate fail, so that the light beam can be transmitted to a light emitting surface of the light guide plate, and exits from the light emitting surface of the light guide plate. However, the conventional optical microstructure can only guide the light beam to the light emitting surface of the light guide plate, but cannot enable the light beam to exit in a desired angle. Generally speaking, in order to modify a travelling direction of the light beam that exits from the light emitting surface of the light guide plate, the conventional light guide plate is equipped with a plurality of optical films to enable the light beam to exit in a desired angle. In this way, not only a material cost of the backlight module is increased, but also an energy loss of the light beam is incurred when the light beam is reflected or refracted between the optical films, thereby causing light utilization efficiency of the backlight module to decrease.
Taiwan Patent No. I331695 discloses a light guide plate, and the light guide plate includes a plate body, a plurality of microstructures, and a plurality of protruding structures. Taiwan Patent No. M264504 discloses a microstructure, and the microstructure is in the form of a water drop, and is distributed on a lower end surface of a light guide plate in a protruding manner. U.S. Pat. No. 7,334,934, China Patent No. 100370329, U.S. Patent Publication No. 20060104089, and U.S. Pat. No. 7,252,424 all disclose a light guide plate, and a reflective surface of the light guide plate has a microstructure. Taiwan Patent No. I321250 discloses a light guide plate, and the light guide plate includes a light transmissive substrate, a first microstructure, and a second microstructure. Taiwan Patent No. I246576 and U.S. Pat. No. 6,712,481 disclose a light-emitting panel assembly including a light-emitting panel member, in which individual light extracting deformities of well defined shapes of patterns in or on one or more panel surfaces are used to produce a desired light output distribution through the panel member, at least some of the deformities have inclined surfaces for reflecting or refracting light striking the inclined surfaces which leaves the panel member in a desired angle distribution and have a curved surface curved transversely in a width direction of the deformities for reflecting or refracting additional light striking the curved surface, so as to distribute the light across the panel member to provide a more uniform distribution of the light emitted by the panel member.